Look at someone with new eyes/knock the socks off someone
刮目相看
Lv Meng (lǚ méng 吕蒙) was a general of Wu during the Three Kingdoms Period (三国时代，220-280AD).
三国时期(220-280)，吴国有一个叫吕蒙的将军
He was born in such a poor family that he did not get any chance to go to the school when he was a child.
吕蒙出生在穷苦人家，小时候没有机会上学。
However， there was still less time for reading when he served in the army after he grew up.
长大后他参了军，看书的时间更少了。
Once the king of Wu summoned Lv Meng and said to him， “Since you are now a general in power， you had better read some books to widen your horizon.”
一次，吴国的皇帝召见吕蒙，对他说：“现在你是大将军了，应该多看看书开阔眼界。”
Lv Meng answered， “I am so busy with military affairs that I am afraid I have little time to read.”
吕蒙回答道：“军中的事务这么忙，我恐怕没有时间读书。”
The King said， “Are you busier than I am? Even I often find time to read books on the art of war and gain much benefit from them. To read more about the experience left by our ancestors will make you progress.”
吴国的皇帝说：“你难道比我还忙吗?我常常抽空阅读兵书，从中得到了不少好处。多看看前人的经验之谈，你会有更大的进步。”
Lv Meng then did according to what the king said. He concentrated himself on reading history and military writings.
吕蒙接受了皇帝的建议，从此开始专心阅读，看了很多历史和军事书籍。
On day， Military Governor Lu Su visited Lv Meng and was surprised to find that Lv Meng had become very knowledgeable.
一天，主帅鲁肃来拜访吕蒙，惊讶地发现吕蒙变得很有学问。
Lu Su， who held Lv Meng in contempt earlier， said， “I did not expect that you would know so much besides fighting! You are not the one you used to be!”
曾经非常轻视吕蒙的鲁肃说：“我以为你只会打仗，没想到你这么博学。你已经不是过去的那个吕蒙了!”
Lv Meng replied， “You should look at a person with new eyes even only after a three days‘ separation.”
吕蒙回答道：“即使你和别人只分开了三天，三天后再遇到他时也不能用三天前的老眼光来看待他。”
Today， when a person does something that causes others to see him differently， we can say that people “look at him with new eyes.”
今天，当一个人做了某些事，令别人另眼相待时，我们就可以说，对他“刮目相看”了。
英语中有一个与“刮目相看”意义大致相近的短语，叫做“knock the socks off”，直译就是“把~的袜子都撞掉了”，也就是让某人刮目相看的意思啦。同样的，如果别人让你刮目相看的话，你也可以说：“Hey，dude~You really knocked my socks off!”
Next quarter I really want to knock the socks off the competition.
下一季我非常希望可以让竞争对手刮目相看。